Home Improvement Expert Danny Lipford

How to Identify the Cause of Brown Spots In Your Lawn

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Brown spots in lawns are frustrating to deal with! Just when you think you’ve done everything right, suddenly there’s a patch of grass that’s dead or dying. There are a number of causes of brown spots in lawns, from insects to disease to human error.

To get to the bottom of the situation, you’ll have to do a little old-fashioned investigating. Here’s a checklist to help you determine the cause of brown spots in your yard.

Human and Animal Damage

Unfortunately, it’s very easy for us (and our pets) to damage lawns. Some common causes of brown spots include:

  • Dull Mower: Dull mower blades tear your grass, causing damage and gradual death to the grass.

    Remedy: Sharpen your blades in fall and spring. After mowing, examine your grass to see if the mower is cutting cleanly.

  • Scalping: If your mower blade is set too low or there are lumps in the lawn, it can cut the grass too short and cause damage.

    Remedy: Practice proper mowing techniques by raising your mower blades, and smooth out high spots by digging up the sod, removing some of the soil underneath, and replacing the sod.

  • Chemicals: Gasoline, fertilizer, herbicides, and pesticides can cause dead spots if spilled. If fertilizer is applied unevenly or incorrectly, it can burn the grass. Even insect repellents can burn your lawn when sprayed on the grass blades.

    Remedy: Pour chemicals, fuels, and sprays on your driveway, not on your lawn, and follow application directions.

  • Animal Urine: Dogs are the most common culprit, but large birds and other animals can cause urine spots, too. Urine usually causes your lawn to turn yellow in spots, sometimes with a bright green ring around the edges where the diluted nitrogen in the urine acts as a fertilizer.

    Remedy: Check out our article on How to Keep Dogs From Damaging Your Lawn for tips.


Take a sample of stems, roots, and soil for analysis.

Poor Growing Conditions

The conditions in your yard may be unfavorable for grass to grow:

  • Poor Soil: Soil quality can vary in your lawn, and poor soil can occur in patches, causing brown, bare areas or moss.

    Remedy: Take a screwdriver and push it into the soil. If it doesn’t go easily, your soil is likely compacted. Try aerating and top-dressing to incorporate organic matter in the soil. When you aerate, take a look at the plugs, to see how the quality and texture of your lawn varies in different spots. Keep this in mind as you amend and improve your soil.

  • Buried Debris: I once puzzled over a brown patch for weeks before finding an old piece of buried lumber under the grass.

    Remedy: While you’ve got that screwdriver handy, poke around a little to see if anything is underneath the sod.


  • Compacted soil.

  • Erosion: Water tends to run off slopes, taking grass seeds and young shoots with it, and leaving bare ground or dried out areas behind.

    Remedy: Aerate your lawn to increase water absorption. If the slope is steep, consider building terraces or planting groundcover.

  • Roots: Large trees or shrubs usually win the battle for water and nutrients. The area under trees is notoriously difficult for growing grass.

    Remedy: Consider mulching or naturalizing areas under trees and shrubs.

  • Drought: Lawns need one inch of water per week, either from rainfall or irrigation. Dry, compacted spots are more easily drought-damaged.

    Remedy: Keep an eye on dry, sunny spots, especially if your soil drains poorly. If you irrigate, make sure your entire lawn is watered evenly.

  • Dormancy: Cool-season lawns can go dormant during the heat of summer while warm-season lawns go dormant during the winter. If your lawn has a mix of grasses, you’ll have curious brown patches as some areas go dormant while others stay green.

    Remedy: Seasonal dormancy is normal, but make sure your lawn is healthy and strong to prevent unnecessary browning.


Brown spots caused by dormant Bermuda grass mixed with green fescue.

Common Lawn Diseases and Pests

If you’ve eliminated all the above causes, it’s time to move on to some of the more serious diseases and pests that plague lawn grasses. Some of the most common culprits are:

  • Thatch: Thatch is a buildup of decaying grass blades that can build up so thick that it chokes out healthy grass.

    Remedy: Remove thatch if it is more than ½” thick.

  • Grubs: Grubs are a common problem in mid to late summer, and most easily identified when your sod easily pulls back from the ground like a carpet.

    Remedy: Pull back a section of sod and inspect for fat, white curved worms. More than ten per square foot can cause lawn damage. Grub control products are available at your garden center.

  • Chinch bugs: Chinch bugs are a common summer pest in warm-season lawns, especially in hot sunny patches beside driveways and sidewalks.

    Remedy: Inspect your lawn closely, and look at your shoes as you walk through the grass – you should be able to spot the small black and white adults. They’re resistant to many pesticides, but there are products available to target them.

  • Other insects: Caterpillars and other pests can live part of their life cycle in lawns.

    Remedy: Watch your lawn closely – look for crawling and munching insects and for grass blades that look eaten. Also watch for birds and wasps feeding on these pests in your lawn.

  • Fungal Diseases: Brown patch and other fungal diseases thrive in moist conditions, most often in midsummer (when nights and days are hot and humid) and spring (as snow melts). They may show up as circular or irregular brown spots, or you may notice a spotting or infected pattern on the blades or a generally dying/thinning out.

    Remedy: Increase air circulation and sunlight as much as you can, to make your lawn less inviting to fungus. Note the size and shape of the damage as well as the frequency of watering, fertilizer, mowing habits, and sunlight in order to diagnose the disease correctly. Take a sample of the affected grass (blades, roots, and soil) to your local cooperative extension office for analysis.

Further Information



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13 Comments on “How to Identify the Cause of Brown Spots In Your Lawn”

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  1. Jessica Says:
    December 14th, 2009 at 2:09 pm

    Sweet, thanks for the info. I had my sod installed by Evergreen Turf and was looking for general lawn-care tips so I can maintain my lawn myself.

  2. Randy Lauhoff Says:
    December 26th, 2009 at 5:24 pm

    use cornmeal to cure brownpatch

  3. Evelyn Says:
    April 25th, 2010 at 3:00 pm

    I bought a home the has St Augustine grass. The grass has brown patches. I was thinking of replacing those patches or is their something else I can do. And if I do replace the pacthes I would like to put fresh soil. Should I use black cow or what should I put down so the new patches wont die.

    Sincerely

    Evelyn Baez

  4. BILL Says:
    July 29th, 2010 at 8:46 pm

    I HAVE BEEN WORKING ON MY BACKYARD FOR SEVERAL YEARS WE HAVE TO PLANT NEW EACH YEAR, WE HAVE BROUGHT IN NEW DIRT FERTILIZED RESEEDED AND THE SAME THING HAPPENS OVER AND OVER AGAIN. GRASS GROWS VERY WELL AND THEN OVER NIGHT THE GRASS DIES IN LARGE SPOT IT HAPPENS IN THE SAME SPOTS OVER AND OVER AGAIN.YES WE HAVE DOGS THEY ARE NUTERED AND WALKED OUTSIDE THE YARD, WE ALSO HAVE OAK TREES AND HAVE USED MANY DIFFERENT KINDS OF SEED WE ARE STUMPED

  5. David Says:
    March 14th, 2011 at 11:39 pm

    Water them daily for a week. Get some liquid nutrients and mix them with a steroid in a 55 gallon then spreed around the trees and bushes. It will stimulate the roots and plants will grow.

  6. Nabil Abdalla Says:
    March 30th, 2012 at 12:50 pm

    for years I get brown patches every fall and gradually gets green in the spring time, I planted a new grass and still doing the same thing. finally I used weed killer to kill the grass and its roots( roots are so thick and and spread every where) but still have the same problems and it spreads all over the yard gradually. what should I do?

  7. van Johnson Says:
    August 9th, 2013 at 1:36 pm

    large dead spots in lawn, I had them for years. If you live down south, the culprit is more than likely Mole Crickets, They will destroy a lawn in a short time, If not treated they will return year after year. Triazicide Insect Killer, made by Spectracide, from Home Depot will get rid of them. Also kills Fleas,Fireants, and most other lawn pests for entire season.

  8. Robert Delisle Says:
    May 21st, 2014 at 2:17 pm

    We have light green spots of grass in our grass. A lawn care place told us it was deer urine. It is getting worse.
    Can this be deer urine and if so how to stop them from urinating on our grass. Neighbors don’t seem to have so I thought it might not be deer urine as we were told

  9. don adkins Says:
    May 28th, 2014 at 8:39 am

    I have what they call spring kill in my yard.Several brown spots soil is tight,what can I do to get back my pretty lawn?

  10. Robert Delisle Says:
    May 28th, 2014 at 10:18 am

    You sent me postings on brown spots these are definitely not brown spots but real light green circle patches in my lawn. I have NO DOG. Could it be from deer urine??
    Thank you.

  11. Naier Says:
    June 18th, 2014 at 9:38 am

    Hello,
    We have new sod fescue grass almost a month , recently the grss get thin and later becom,brown patch. Many different spot. Our water irgration is correct , how do I pervent from this matter. Our gardener mentioned la k of water , I ve seen even the place has water has same problem.

  12. bruce grashel Says:
    June 26th, 2014 at 9:30 am

    my brown patches look like small areas of brown blades of grass, like above ground thatch. have not used anything but milorganite and the spots showed up before I even used it. could it be a fungus? thanks

  13. Brenda Says:
    July 2nd, 2014 at 12:59 pm

    When I cut my grass using either of my 2 riding mowers, I get light spots that cause the grass to turn brownish yellow and then dies out. When I use my push mower this doesn’t happen. I checked to see if they are leaking gas, but didn’t find any evidence of it. What else could it be. Also is there a way to raise a riding mower that is too low even on its highest setting.

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